Overheating can be a problem for machinery when it is run aggressively for an extended period of time. An overload prevention system can be used to monitor operations and protect the machinery from overheating. For example, the current load in the motor of a loader can jump to greater than 1.5 times its rated value when the operator digs aggressively in a pile. This aggressive digging can be a necessary feature of the loader, so the overload prevention system can be designed to allow the aggressive operation for a limited time and then begin to decrease the torque or other output of the loader to prevent the motor or other components from overheating.
An overload prevention system can monitor and control parameters such as current, torque, time constants, etc. for the system to prevent overheating. When controlling these parameters for the entire circuit, the overload prevention system must use the weakest parameters for the circuit to ensure that no component of the circuit overheats. However, the various components of the circuit may have different parameters describing their heating profiles and potential overheating. For example, a motor may have a higher rated current and a lower time constant while cables connecting the motor to other components of the circuit may have a lower rated current and a higher time constant. To protect the entire circuit without risking overheating of either the motor or the cables, an overload prevention system would use the lower current rating of the cables and the lower time constant of the motor. This will protect the entire circuit from overheating but will limit the circuit in performing operations due to limits activated by the overload prevention system. Of course, the circuit may have a plurality of components, not just two, with different heating parameters that can be protected separately.
It would be desirable to have an overload prevention system for preventing overheating of the various components of a circuit that protects the entire circuit from overheating while also allowing the circuit to perform operations with fewer limitations due to the overheating protection.